Supplementary/Charge

Could there be skills that can be activated for a certain period of time?

Also I read on the skill rules that some skills could be charged to cause a more powerful damage however, it didn't specify any more rule as to how much would the damage increase be per charging time and what's the limit?

Cast Time:While most skills do not have a cast time, it is possible to set up one. Skills with cast time are much more powerful than normal. With every posts a skill is required to charge, its damage will increase by one rank.

Wouldn't say so, diesnt mame too much sense. With a buff you are increasing the amount of power in your body for a fixed period of time, while with an attack it's (usually) sudden and just a quick burst of power.

how many post would the maximum allowable duration for a buff then? So I can't make it as "till mana supply last"?

Just like on FTRP, I have offensive spells that I can use for a long period of time, though with the damage being ranked down. Say for example, conjuring a weapon type spell without the Arc of Embodiment spell would need a spell to be supplementary. Or perhaps some skills such as the Demon Hunter's immolation in Warcraft III. Wouldn't that be applied here as well?